'Things are not what they seem," a taxi driver warns Aomame, as she chooses to hop out of his cab.

You probably wouldn't buy the latest Murakami for a slice of gritty realism, so it's reassuring that Aomame's decision pitches her headlong into a different reality, conveyed in Jay Rubin's lucid translation with plenty of zest. Somehow, 1984 has closed to Aomame, and the sequence of bizarre events that unfolds suggests that she has been drawn into a new universe which looks much the same, but has two moons. The landscape is similar enough for her to name it 1Q84, the Q standing for question, while she puzzles out how her own destiny is tangled up in the moral and procedural framework of this new reality.

Alternate chapters of 1Q84 explore Tengo's story. A teacher and budding novelist, Tengo is persuaded by his editor to rewrite 17-year-old Fuka-Eri's inspirational debut manuscript. With her consent and his polish, her mystical story of malevolent "little people" with sinister powers making a portal from their world to ours becomes a bestseller. But media scrutiny threatens their cosy ghost-writing scam, and unearths Fuka-Eri's dysfunctional childhood in a closed religious cult. How the paths of Aomame and Tengo converge provides the steadily growing excitement of this huge, engrossing novel which was published in Japan in two volumes.

Aomame's story refreshes Murakami's habitual theme of an individual descending into some sort of underworld to confront his or her destiny and explore the nature of reality. Murakami uses the surreal confidently, from portals at the bottom of wells in his subtly textured 1994 epic The Wind-Up Bird Chronicle to the six-foot cellar-dwelling superhero frogs found in his 2002 collection After the Quake. His landscapes are charged with fantastic figures that hold portentous significance, and like some of his most substantial work, 1Q84 offers a loose political allegory.

The cult bears resemblance to Aum Shinrikyo, whose 1995 terror attacks on Tokyo's subway Murakami analysed in his reportage published as Underground. Coupled with 1Q84's themes of violence against women and institutionally supine policing, this suggests that Murakami is probing a malaise at the heart of Japanese society.

Loneliness has been Murakami's stock in trade, from the melancholia of his bestselling Norwegian Wood to the more mournful protagonist of Sputnik Sweetheart. 1Q84 is driven by outsiders in a culture that prizes conformity. Identity and belonging, the porous membrane separating stories and reality, and a whole host of Murakami icons from talking cats to one-way portals all contribute to this rich and often perplexing mix. But ultimately, 1Q84 is a simple love story that ends on a metaphysical cliff-hanger.

A year after publication, Murakami dashed off a third volume that purportedly brings resolution, but UK readers will have to wait until the end of the month to digest this delicious paranormal stew in its entirety.